Circuit interrupter



Feb. 28, 1933. L, w, DYER 1,899,612

` .cIRcul'r INTEgRUPTER Filed April 4, .1930

Fig 7.

VIVI

INVENTOR Lloyd M/Dyer'.

BY ATTORNEY Patented Feb. 28, 1933 y UNITED' STATES PATENT OFFICE LLOYD W. DYER, OF SWISSVALE, PENNSYLVANIA, ASSIGNOR WISTINGHOUSE ELECTRIC MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA CIRCUIT INTERRUPTER My invention relates to circuit interrupters and particularly to arc-extinguishing devices therefor that are immersed in a fluid.

lt has been demonstrated by experiment that the most important factors in the interruption of alternating-current arcs are; first,

the rate of rise of recovery voltage immediately following a current zero in the cycle Wave and, second, the rate of deionization of the gases between the arcing contact members after the current zero point.

The rate of rise of recovery voltage can be somewhat controlled by employing resistors or condensers in conjunction wlth the circuit interrupters, while the re-combination of ions in the arc space depends entirely upon the. design and construction of the circuitinterrupting device itself.

My invention relates to deionizing devices for circuit interl'upters of the oil-immersed typo and has for its object the retention'of a portion of the liquid thereof adjacent to the arc path where it will be decomposed by the arc to liberate a deionizing gas which will pass turbulently into and out of the arc stream.

Another object of my invention is to provide a circuit interrupter of the above'described type ha-vinga device thatshall direct gases radially into the arc stream from all points of the periphery thereof at intervals along the arc length, which gases may be vented out of the arc stream between the various said intervals.

A further object of my invention is to provide an arc-extinguishing device of the abovedescribed type that is immersed in a liquid, and having ya plurality of pockets disposed at intervals along the arc length that shall retain a portion of the liquid adjacent to the are core when an arc is established between the contact members.

'A still further object of my invention is to provide a device of the above-described tvpo with a plurality of cooling surfaces that l-lmll divide the vented gases to further cool und (loionize them.

A further object of my invention is to retain a substance in close proximity to the are stream, that shall provide relatively cool surv bridging 1980. Serial N0. 441,580.

faces and nuclei, in the presence f an arc, upon which recombination of ions in the arc stream can occur.

For a more complete understanding of the nature and objects of my invention, reference should be had to the following description, taken in conjunction with the accompanying drawing wherein:

Figure l-is a sectional view, in elevation, of a circuit interrupter embodying my invention,

Fig. 2 is an enlarged vertical sectional view, of a ragment of the arc-extinguishing device shown in Fig. 1,

Fig. 3 is a sectional view of a modified form of the arc-extinguishing device,

Fig. 4 is ay transverse sectional view of the arc-extinguishing device shown in Fig. 3, .taken along the line IV-IV thereof,

Fig. 5 is a vertical sectional view o f a unit' of an arc-extinguishing device similar .to that shown in Fig. 3, but disclosing another embodiment of my invention,

Fig. 6 is a vertical sectional view of a portion of a structure similar to that shown in Fig. 2, but disclosing additional features of minvention,

ig. 7 is a plan view of the structure shown in Flg. 6, an

Figs. 8 and 9 are vertical sectional views of an arc in my deionizing structure and disclosing the path of movement of the deionizinggases in the arc stream.

y invention comprises, in general, a casing 1 having a cover 2 that supports conductor bushin 3 and 4, in a manner that is well known in t e art. The bushings 3 and 4 suport the contact members 5 and 6, respectivey, which are conductively joined by the member 7 and the rods 8 and 9 which are carried on the ends of the last said mem- The bridging member 7 is su ported on a lift rod 10 that extends throug the cover 2 and is connected to o erating mechanism (not shown). This meciianism is actuated to move the rods 8 and 9 longitudinally to connect or to disconnect them from the contact members 5 and 6, respectively, to complete or interrupt an electric` circuit. Deionizing structures 11 and 12 are supported on the terminal members 5 and 6, respectivel and are immersed in an arc-quenching liquid 13 that is contained within the easing 1. This liquid 5 ispreferably an oil that freely evolves a gas of low molecular weight when incontact with an arc, although it is to be understood that any liquid having satisfactory dielectric properties and that readily evolves gases in the presence of an arc and which possesses the desired deionizing qualities, may be substituted for the oil.

In the copending application of J. Slepian, Serial No. 411,271, filed December 3, 1929,

vention, a deionizing device is disclosed which is similar to the deionizing device of my invention, but comprises a series of spaced oil-soaked plates having apertures in which the arc is drawn and held in fixed relation to the oil retained in the plates. In devices of these types, the oil is rapidly decomposed by the are, and the gases that are evolved pass turbulently through the are stream and the ionized space remaining after the arc is extinguished. The cooled gas particles form centers in the ionized space upon which the ions rapidly recombine to form un-ionized layers that increase in thickness at such a rate that .the rise of recovery voltage after the arc is extinguished is never sufficient to cause the re-initiation of the arc.

My invention relates to devices for supplying oil to the are stream that are constructed of materials that are only slightly affected by the arc and which, therefore, substantially v retain their original dimensions.

In my present arrangement, illustrated in Fig. 1, the deionizing structures 11 and 12 comprise two or more insulating plates 14 that are spaced apart a predetermined distance by the insulating spacers 15 as shown in Fig. 2. Rods 16 extend through the spacers 15 and the plates 14 to form a unit structure that is suspended from the terminal members 5 and 6, respectively. A hole 17 isv provided in the center of each of the plates 14, these holes bein alined in the deionizing structure in ordert 'at the contact rods 8 and 9 may open or to circmt-closed position. Whenan arc is drawn 1n a quenching liq` uid, a gas bubble forms about the are stream and prevents the eater portion of the arc. core from contacting with the liquid. The only portion of the arc that continually 'engagesthe liquid is that portion that impinges on the movable contact member vand is drawn -into the liquid as thecontact member is being moved. Thel plates 14 laie employed to increase the number of contacting points'of the arc core with theliquid. The film of liquid retained on the periphery of the hole 17 remains 'toibe decomposed by the are after the`bubble, formed about the arc core, has

and assigned to the assignee of the present inpass therethrough when. moved to circuit-- results and substantiated the belief that the film of liquid on the surface of the holes was too far from t-he arc stream to be rapidly decomposed by the arc.

The small holes limit the expansion of the arc and should, therefore, have an area that is equal to, or less than, the cross-sectional area of the arc core. When the are is so confined the arc voltage increases With the increase of current, as the arc is unable to eX- pand at the point of confinement, the current density also increases. The concentration of the current increases the rate of decomposition of the liquid which is fed radially into the arc core, at each plate around the entire periphery of the arc.

In order to prevent any increase in the size of the hole, in the presence of the concentrated arc current, it was necessary to employ a material in constructing the plate that would not be affected or would be only slightly affected by the arc. A molded asbestos compound produced satisfactory results, but

vplates made from libre proved to be the most reliable in operation. The latter material is only slightly eroded by the arc, which erosion proved beneficial in preventing any metallic deposit from forming on the -walls of the holes 17. The libre material proved further beneficial in supplying to the arc stream additional 11n-ionized gas when the material was' decomposed, by the arc. This gas effected the same deionization of thev arc path as that produced by the gas of thev decomposed liquid, the combination of which materially increased the rate of recombination of the ions in the arc stream.

The deionizin device shown in FigsB and e comprises a p urality of units 18 that are composed of two or more plates of insulating material referred to heretofore. The units are separated from each other by insulating spacers 15 that are mounted on rods 16 to form a unit structure. Each of the units 18 is provided with a hole 17, through the center thereof, that is less than 7/8 of an inch in diameter. The conducting rods 8 and 9 extend through the aligned holes 17 to complete acircuit with the terminals 5 and 6, respectively, and to draw ares when the contact rods are separated therefrom when moved downwardly to open-circuit position.

The surface of the sides of the holes in the lll .and deionize these gases,

composite plate 'units 18 is much greater than the surface of the holes in the single plates 14 and, consequently, larger volumes of the un-ionized gas will be liberated at each of the confining vportions of the units, because of the greater amount of oil clinging to the surfaces of the holes. As the rate of deionization (of the arc) is increased with an increase in the amount of un-ionized gas that is continually being' fed into the. arc stream, theunits 18 have a distinct advantage over the thin plates 14.

The unit 18 shown in Fi 5 is provided with a central plate 20 thatas a hole 21 in the center thereof, having a greater diameter than the holes 17 in outer plates 22 and 23 of the unit. The hole 2l of the plate 20 forms a pocket in the unit 18, in which some of the quenching liquid 13 is trapped and retained to be available for feeding into the arc stream when an arc is'established through a plurality of units containing the pocket 21.- Where the term pocket is used in the claims, it means a recess having a size which is large com ared to the size of the pores in the material of the plates.

As pointedout above, the hot ionized gases are forced out of the arc stream into the space 18 between the units 14 by the fresh gas that is continually supplied to the arc stream. In order to more effectively cool I provide a plurality of vertical plates 24 disposedradially in the space 19 about the holes 17, as shown in Figures 6 and 7. When the gas is forced through the space 18, it will be divided into a plurality of sections by thev plates 24, which will cool the gases and cause them to recombine on the surfaces of the plates. The

lates 24 are further useful in resisting the gow of oil away from the arc stream, some of which will be retained adjacent to the arc path to be decomposed by the arc, while portions of the remainder will aid in the cooling of the escaping gases.

The above-noted motion of the gas into and out of the arc stream is illustrated in Fig.' 8 of the drawing, desi ate the path of travel of the various particles of the gas evolved from the decomposition of the oil 13. It will be seen, from the direction of the lines and the arrows, that the gas not only passes into and out of the arc strea-m at intervals throu hout the arc length but that this'passage o the gas takes place radially alongthe the arc. That is to say, the gas is supplied to the are core radially from every point around itsbv entire circumference. This flow of gas through the arc stream begins to take place assoon asthe arc is initiall drawn, since the liquidis not closely confined and `is free to move as the gas is formed by the decomposition of the liquid held along the arc core by the edges of the openings in the wherein curved lines 25- entire periphery of plates. The venting passages between the 1nl the outer tank so that the gases formed by the arc can begin to flow and' produce turbulence in the `arc stream as soon the circuit is initially broken, thus causing the arc to be very quickly extinguished.y

Taking advantage of the discovery that a deionizing gas supplied radially to the arc core at various points throughout its length causes the ions of the arc space to be rapidly combined, I have invented the deionizing structure shown in Fig. 9. In this construction, the plurality of units 18, that are spaced along the arc path, are provided with an annular channel 26 that is connected t0 a plurality of tubes 27, which are spaced radially about the channel 26. The tubes 27 are connected to a source of supply of a deionizing material that may be a powder, gas, or liquid to produce the rapid recombination of the ions in the arcA space referred to hereinbefore. Suitable means, well known in the art, is einployed to connect and disconnect the source of supply to the tubes 27 in relation to the movement of the rods 8 and 9. The movement of the gas into the arc stream from all sides thereof further prevents the highly mobile arc vfrom moving away from the gas which passes directly into the arc vstream and out of it, as disclosed by the lines and arrows of Fig. 9. l

It will thus be seen that Ihave provided a circuit interrupter that establishes an arc in a quenching fluid and a device adjacent to the arc path that retains a portion of said fluid in the vicinity of the arc by which it is decomposed to liberate deionizing vases for effecting the ra idrecombination of, the ions in the arc pat after arc.. extinguishment. The gas is supplied to the arc stream radially at a plurality'of intervals along the arc length and is ventedfrom the arc path between the intervals.

It will also 'be recognized that the distribution of gas sources along the arc is applicable where the 'arcris drawn in air or other gaseous media as well as in the quench. ing liquid specifically described herein. In fact, any device that turbulently injectsa deionizing medium into the arc path along its entire length, or at intervals thereof, in the presence of the arc or after the are is extinguished, falls within the scope of my invention.

.While I have described several embodiments of my invention, it is to be understood by those skilled-in the art that many clmnges, additions, omissions and substitutii'ms may be made therein without departing from thel spirit and scope of my invention, as set forth in the appended claims.

I claim as my invention:

1. In combination with circut-interrnpteicontact members, of unit members each com- Y with said laminations.- Y

prisin a plurality of contiguous insulating yplates aving aliiied holes, the holes in some of the plates of each unit having larger dimensions than the other plates of that unit 5`for forming pockets and a substance which evolves gas when acted upon by an arc retained in said pockets.

2. In combination with circuit-interrupter contact members, of unit members leach comprising more than two contiguous insulating plates having alined holes, the holes in the plates at the center of each unit having larger dimensions than the other plates of that unit for forming pockets, and a quenching liquid surrounding said unit members, a portion of which is retained by said pockets after said contact members are separated.

3. The combination with aliquid-immersed circuit interrupter for alternatingcurrent circuits, of separable contact members, a plurality of insulating members spacedapart and associated with said ccn-V tact members, pockets in said insulating members for'retaining a portion of said liquid therein and means between said insulating members for dividing the space therebetween into a plurality of passages.

4. The combination with a liquid-immersed circuit interrupter for alternatingcurrent circuits, of separable contact meinbers'including a thin rod, a lurality of insulating members having }holes through which said rod extends and is moved to establishV an arc, the said holes being not -substantially greater in width than said rod, and the said insulating members having pockets formed in the periphery of said holes for retaining al portion of said liquid .therein in the presence of an established arc.

5. In a circuit interrupter, an arc extinguishing device including means of insulating material .having an opening therethrough, means for causing an arc in said opening, a plurality of pockets positioned along said opening, said pockets being .closed on all sides except the side leading tov said opening, and a material which evolves gas when lacted lupon by the arc retained in ls aid p pockets in the presence of the arc.

6.. In a circuit interrupter, an are extinguishing device including a stack of laminations of insulating material, openings in said laminationsaorming a passage -through the stack, means` for causing an arc in said openings with the smaller dimensioinand a.

substancewhich'gives oli a large volume of gas when acted'upon by tlie arc cooperating passage, the openings in some of said laminaeeeia 7. In a' circuit interrupter, a pair "of contacts one of which -is-'movable and between which the' circuit throiigh said interrupter is initially broken, an arc extinguishing structure includingl means of insulating material having an opening therethrough in which the arc caused by the initial break of the circuit plays, said means of insulating material having portions at the edge of said opening extending substantially to the path of movement of said movable Contact member, an'outer casing for the circuit interrupter enclosing said arc 'extinguishing structure, said outer casing having a crosssection several times greater than the crosssection of said arc extinguishing structure,

'means along said opening for the are which gives 0E a large volume of gas when acted upon by the arc, and Ventilating means extending from said opening for the arc caused by the initial break of the circuit directly to the space enclosed by said outer casing. 8. In a circuit interrupter, a pair of contacts-one of which is movable and between which the circuit through said interrupter is initially broken, an arc extinguishing structure including a stack of plates of insulating material, said stack having an opening' therethrough in which' the arc caused by the initial break of the circuit plays, said opening having portions of a width not substantially. greater than the width of said movable contact member, an outer casing for the circuit interrupter enclosing said arc extinguishing structure, said outer casing having a cross-section several times greater than the cross-section of said arc extinguishing structure, means along said opening for v Y thelarc which gives ofi' a large volume of gas when acted u on by the arc, and ventilating means exten 'ng from the portion of said opening at whichthe arc is initially formed directly to the space enclosed by said outer casing. y

v 9. `In a circuit interrupter, a pair o-contacts one of which is movable and between `which the circuit through said interrupter is initially broken, an arc extinguishing structure including means of insulating ina-I terial having an opening therethrough in which the arc caused by the initial break ofthe circuit plays, saidV opening having substantially the saine width as said movable contact member, an outer casing for the circuit f interrupter` enclosing said arc extinguishing structure, said outer casing having a cross-section several-times greater than the cross-section of said arc extinguishing structure, and a body of liquid which gives o gas when acted upon by the arc in said outer casing, a plurality of pockets formed in the wall. of said opening Iin'which the arc plays,

said pockets'being closed on all sides except the side leading to said opening.

10. In a circuit interrupter, a pair of contions of a width not substantially greater means extending laterally from the path Y having portions of a wid than the width of said movable contact member, an outer casing for the circuit interrupter, a body of liquid in said outer casing surrounding said arc extinguishing structure, said liquid adjacent the arc extinguishing structure being free to move immediately upon the drawing of the arc `and ventixi(y where the arc plays to said liquid in the outer casing outside of the arc extinguishing structure.

1l. In a circuit interrupter, apair of contact members, one of which is movable to initially break the circuit by causing an arc, an arc extinguishing structure including means of insulating.material positioned adjacent the point where said contacts first separate, said means of insulating material having an opening therein through which said moving contact draws the arc, said opening having portions at its periphery extending substantially to the path of said movable contact member, an outer cuit interrupter, a bod casing surrounding sai arc extinguishing structure, and venting means extending through the arc extinguishing structure from the path where the arc plays to the liquid in the outer casin said venting means permitting ilow of fluid at any time after the circuit Y is initially broken. 12. In 'a circuitinterrupter a pair of contact members connected to ofthe circuit interrupter and a brid g bar including moving contact members gli? com- Yof liquid in said pleting the electrical circuit between said contact members connected to the terminals, astack of plates of insulating material for each cooperating pair of said contactmembers, said stack having an opening therethrough in which the arc lays, said opening not substantially greater than the width of the movable contact member a enclosing said stacks of plates m said bndgin bar, said casin being the only enclosure or said stacks o plates, a body of liquid in said casing, and ventg means extending through each ofA said stacks of plates from the openings in which the arcs play to said body of liquld.

13. In a circuit mterrupter, a pair of contacts one of which is movable and between which the circuit through said interrupter is initiall broken, an arc extinguishing structure including means of insulating material having an o nin therethrough inl which the'arc callas-.se by e initial break of the circuit plays, said means of insulating material having portions extending substantially to the path of said movable contact member, an outer casing for the circuit interrupter enclosing said arc extinguishing structure, and a body of liquid which gives ofi' gas when acted up n by the arc in said outer casing, a vplura ity o pockets formed in the wall of said opening in which the are plays, said pockets being closed on all sides except the side leading to said o ening, and venting means permitting flow oi) fluid from said opening into said body of liquid in said outer casing at any time after the circuit is broken.

In testimony whereof, I have hereunto subscribed my name this 31st da of March, 1930. LLO W. DYER.

casing for the cirthe terminals ios 

